P2 Locomotive Company and related matters

Thank you very much for you information sir!

 

Only Cock O'the North was fitted "experimentally" with the ACFI plant. As is known it wasn't fitted to the rest of the class. From most accounts it didn't work out as successful as hoped/planned, in comparison to Earl Marischal.

 

Thanks for correct me sir

 

"The ACFI feed water heater fitted to No. 2001 proved troublesome, requiring, as it did, exhaust steam to pre-heat the injector supply which required the locomotive to run with the regulator constantly open, something that was not possible on the Aberdeen route. The locos did prodigious work hauling 550 ton trains on the Aberdeen route but No. 2001 had an appetite for coal." - from the PSLC archive.

Foxy

 

Every day a school day, thought injectors only worked with cold water!! On our tank engines at the WSR on warm days they are nightmare.

 

The ACFI feedwater heater was not an injector and, denied the physics available to a cold water supply, relied on a pump to overcome boiler pressure, they also needed a constant supply of exhaust steam (requiring the regulator to be open) which is where some of the perceived economies were lost.

Foxy

 

Didn't 2001 actually have a steam powered feed pump rather than an injector as part of the ACFI system?

 

I think that you'll fin d that the ACFI herated the delivery water FROM the injector to the boiler, so the feed water to the injector was still cold, well tender temperature

 

Been beaten to it, seems that ACFI used a pump instead of an injector.

 

Hot water injectors are available and pretty much always have been. Life is simpler with cold water but can be quite hard to come by in many places.

i'm very much surprised that you have problems with hot feed water on the WSR, especially with GWR injectors.

 

As far as I know the ACFI (Societe l'Auxiliaire des Chemins de Fer et de l'Industrie) feed water heating apparatus consisted of two heater drums and a single steam cylinder which operated two water pump cylinders. The first of these drew water from the tender into one of the drums where it mixed with exhaust steam. The heated water flowed into the second drum, where the second pump drew it into the boiler. All three cylinders were double acting. Maintenance costs of the ACFI apparatus were found to be higher than the savings in fuel. One of the main problems was that the system tended to scale up and required acid cleaning every six weeks. This cleaning in turn tended to damage pipe joints. I believe both the GER and LNER experimented with the kit.

Foxy

 

From what I've seen, the GWR injectors as fitted to the W&L's twins have provided some 'interesting' experiences over the years. Granted, these were SG sized kit, tacked on during 'Swindonisation'.

Exhaust steam injectors seem to have given UK designers their share of headaches over the years, though when the cousins appear to have mastered them, quite why they're regarded as a bane this side of the pond has always been unclear to me.

 

Sounds like a complicated way to pre heat feed water, Sentinels just had a coil of copper pipe in the feed to the clack enclosed in a box on the exhaust, and that makes the water hot enough to raise a blister if you touch the pipe.

 

Different cones had to be sent to the Middle East for the 8Fs sent there in World War II, the usual sizes being unreliable in desert temperatures. I also understand that condenser fitted locos were also given a feed pump for when the condensed steam raised the temperature of the water in the tanks to above what the injectors could deal with.

 

Should we have a 'Well, I never knew that!' button?

 

In many respects injectors are efficient and economic but..... they rely on the temperature differential to keep them working, if this is reduced they become less efficient. I have been on the footplate of a dark blue locomotive that was sat in the blistering July sun for an afternoon while it was being serviced. Once it had picked up its train for the return journey trouble was experienced keeping the injector on, a problem that was only resolved when the tender was re-filled with cold water - so it appears even a few degrees can make a difference!

Foxy

 

Due to having to run 'Silently' the Wisbech and Upwell tram locos exhausted into the tank, which formed the footplate and ran with the blower open (silent?) this was the same for London locos working thro' 'The Pipe' to New Cross Gate. despite this 'Condensing' arrangement the water had to be dumped and the tank re-filled every journey in order to keep the injectors working, shudder to think about oil in the feed water.

 

4160 was especially bad for it, not terrible but would do it.

 

Have just read the latest Mikado Messenger. I'm very impressed to see that the rate of progress has warranted the appointment of an assistant engineer

This is just marvellous news.

 

It is easy and cheap being armchair engineer so here I go.
The first 6 were rebuilt due to long fixed wheelbase(probably) and mr Chapelon was not too impressed by fuel economy on french teststand.
Mr Gressley had learnt his trade under mr Webb.
If the P2 had been built as Webb three-cylinder compound ,there would have been space for movement of first coupled wheelset in a Krauss Helmholtz truck .
Reason is that instead of three 21 inch simple, two high pressure cylinders of 16 inch outside would have been enough.
And an 32 inch low pressure between frames of course
The outside cylinder centerline distance could have been 5 inch further apart making room for crosshead to pass front coupling pin.
Is it planned to sell a 3D CAD model of P2 and what is cylinder diameter and center-distance of the soon to be manufactured cylinder block?